/* * Copyright (C) 2008 Oracle. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include <linux/kernel.h> #include <linux/bio.h> #include <linux/buffer_head.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <linux/time.h> #include <linux/init.h> #include <linux/string.h> #include <linux/backing-dev.h> #include <linux/mpage.h> #include <linux/swap.h> #include <linux/writeback.h> #include <linux/bit_spinlock.h> #include <linux/pagevec.h> #include "compat.h" #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "btrfs_inode.h" #include "volumes.h" #include "ordered-data.h" #include "compression.h" #include "extent_io.h" #include "extent_map.h" struct compressed_bio { /* number of bios pending for this compressed extent */ atomic_t pending_bios; /* the pages with the compressed data on them */ struct page **compressed_pages; /* inode that owns this data */ struct inode *inode; /* starting offset in the inode for our pages */ u64 start; /* number of bytes in the inode we're working on */ unsigned long len; /* number of bytes on disk */ unsigned long compressed_len; /* number of compressed pages in the array */ unsigned long nr_pages; /* IO errors */ int errors; int mirror_num; /* for reads, this is the bio we are copying the data into */ struct bio *orig_bio; /* * the start of a variable length array of checksums only * used by reads */ u32 sums; }; static inline int compressed_bio_size(struct btrfs_root *root, unsigned long disk_size) { u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); return sizeof(struct compressed_bio) + ((disk_size + root->sectorsize - 1) / root->sectorsize) * csum_size; } static struct bio *compressed_bio_alloc(struct block_device *bdev, u64 first_byte, gfp_t gfp_flags) { struct bio *bio; int nr_vecs; nr_vecs = bio_get_nr_vecs(bdev); bio = bio_alloc(gfp_flags, nr_vecs); if (bio == NULL && (current->flags & PF_MEMALLOC)) { while (!bio && (nr_vecs /= 2)) bio = bio_alloc(gfp_flags, nr_vecs); } if (bio) { bio->bi_size = 0; bio->bi_bdev = bdev; bio->bi_sector = first_byte >> 9; } return bio; } static int check_compressed_csum(struct inode *inode, struct compressed_bio *cb, u64 disk_start) { int ret; struct btrfs_root *root = BTRFS_I(inode)->root; struct page *page; unsigned long i; char *kaddr; u32 csum; u32 *cb_sum = &cb->sums; if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) return 0; for (i = 0; i < cb->nr_pages; i++) { page = cb->compressed_pages[i]; csum = ~(u32)0; kaddr = kmap_atomic(page, KM_USER0); csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE); btrfs_csum_final(csum, (char *)&csum); kunmap_atomic(kaddr, KM_USER0); if (csum != *cb_sum) { printk(KERN_INFO "btrfs csum failed ino %lu " "extent %llu csum %u " "wanted %u mirror %d\n", inode->i_ino, (unsigned long long)disk_start, csum, *cb_sum, cb->mirror_num); ret = -EIO; goto fail; } cb_sum++; } ret = 0; fail: return ret; } /* when we finish reading compressed pages from the disk, we * decompress them and then run the bio end_io routines on the * decompressed pages (in the inode address space). * * This allows the checksumming and other IO error handling routines * to work normally * * The compressed pages are freed here, and it must be run * in process context */ static void end_compressed_bio_read(struct bio *bio, int err) { struct extent_io_tree *tree; struct compressed_bio *cb = bio->bi_private; struct inode *inode; struct page *page; unsigned long index; int ret; if (err) cb->errors = 1; /* if there are more bios still pending for this compressed * extent, just exit */ if (!atomic_dec_and_test(&cb->pending_bios)) goto out; inode = cb->inode; ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); if (ret) goto csum_failed; /* ok, we're the last bio for this extent, lets start * the decompression. */ tree = &BTRFS_I(inode)->io_tree; ret = btrfs_zlib_decompress_biovec(cb->compressed_pages, cb->start, cb->orig_bio->bi_io_vec, cb->orig_bio->bi_vcnt, cb->compressed_len); csum_failed: if (ret) cb->errors = 1; /* release the compressed pages */ index = 0; for (index = 0; index < cb->nr_pages; index++) { page = cb->compressed_pages[index]; page->mapping = NULL; page_cache_release(page); } /* do io completion on the original bio */ if (cb->errors) { bio_io_error(cb->orig_bio); } else { int bio_index = 0; struct bio_vec *bvec = cb->orig_bio->bi_io_vec; /* * we have verified the checksum already, set page * checked so the end_io handlers know about it */ while (bio_index < cb->orig_bio->bi_vcnt) { SetPageChecked(bvec->bv_page); bvec++; bio_index++; } bio_endio(cb->orig_bio, 0); } /* finally free the cb struct */ kfree(cb->compressed_pages); kfree(cb); out: bio_put(bio); } /* * Clear the writeback bits on all of the file * pages for a compressed write */ static noinline int end_compressed_writeback(struct inode *inode, u64 start, unsigned long ram_size) { unsigned long index = start >> PAGE_CACHE_SHIFT; unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; struct page *pages[16]; unsigned long nr_pages = end_index - index + 1; int i; int ret; while (nr_pages > 0) { ret = find_get_pages_contig(inode->i_mapping, index, min_t(unsigned long, nr_pages, ARRAY_SIZE(pages)), pages); if (ret == 0) { nr_pages -= 1; index += 1; continue; } for (i = 0; i < ret; i++) { end_page_writeback(pages[i]); page_cache_release(pages[i]); } nr_pages -= ret; index += ret; } /* the inode may be gone now */ return 0; } /* * do the cleanup once all the compressed pages hit the disk. * This will clear writeback on the file pages and free the compressed * pages. * * This also calls the writeback end hooks for the file pages so that * metadata and checksums can be updated in the file. */ static void end_compressed_bio_write(struct bio *bio, int err) { struct extent_io_tree *tree; struct compressed_bio *cb = bio->bi_private; struct inode *inode; struct page *page; unsigned long index; if (err) cb->errors = 1; /* if there are more bios still pending for this compressed * extent, just exit */ if (!atomic_dec_and_test(&cb->pending_bios)) goto out; /* ok, we're the last bio for this extent, step one is to * call back into the FS and do all the end_io operations */ inode = cb->inode; tree = &BTRFS_I(inode)->io_tree; cb->compressed_pages[0]->mapping = cb->inode->i_mapping; tree->ops->writepage_end_io_hook(cb->compressed_pages[0], cb->start, cb->start + cb->len - 1, NULL, 1); cb->compressed_pages[0]->mapping = NULL; end_compressed_writeback(inode, cb->start, cb->len); /* note, our inode could be gone now */ /* * release the compressed pages, these came from alloc_page and * are not attached to the inode at all */ index = 0; for (index = 0; index < cb->nr_pages; index++) { page = cb->compressed_pages[index]; page->mapping = NULL; page_cache_release(page); } /* finally free the cb struct */ kfree(cb->compressed_pages); kfree(cb); out: bio_put(bio); } /* * worker function to build and submit bios for previously compressed pages. * The corresponding pages in the inode should be marked for writeback * and the compressed pages should have a reference on them for dropping * when the IO is complete. * * This also checksums the file bytes and gets things ready for * the end io hooks. */ int btrfs_submit_compressed_write(struct inode *inode, u64 start, unsigned long len, u64 disk_start, unsigned long compressed_len, struct page **compressed_pages, unsigned long nr_pages) { struct bio *bio = NULL; struct btrfs_root *root = BTRFS_I(inode)->root; struct compressed_bio *cb; unsigned long bytes_left; struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; int page_index = 0; struct page *page; u64 first_byte = disk_start; struct block_device *bdev; int ret; WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); atomic_set(&cb->pending_bios, 0); cb->errors = 0; cb->inode = inode; cb->start = start; cb->len = len; cb->mirror_num = 0; cb->compressed_pages = compressed_pages; cb->compressed_len = compressed_len; cb->orig_bio = NULL; cb->nr_pages = nr_pages; bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); bio->bi_private = cb; bio->bi_end_io = end_compressed_bio_write; atomic_inc(&cb->pending_bios); /* create and submit bios for the compressed pages */ bytes_left = compressed_len; for (page_index = 0; page_index < cb->nr_pages; page_index++) { page = compressed_pages[page_index]; page->mapping = inode->i_mapping; if (bio->bi_size) ret = io_tree->ops->merge_bio_hook(page, 0, PAGE_CACHE_SIZE, bio, 0); else ret = 0; page->mapping = NULL; if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) { bio_get(bio); /* * inc the count before we submit the bio so * we know the end IO handler won't happen before * we inc the count. Otherwise, the cb might get * freed before we're done setting it up */ atomic_inc(&cb->pending_bios); ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); BUG_ON(ret); ret = btrfs_csum_one_bio(root, inode, bio, start, 1); BUG_ON(ret); ret = btrfs_map_bio(root, WRITE, bio, 0, 1); BUG_ON(ret); bio_put(bio); bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); bio->bi_private = cb; bio->bi_end_io = end_compressed_bio_write; bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); } if (bytes_left < PAGE_CACHE_SIZE) { printk("bytes left %lu compress len %lu nr %lu\n", bytes_left, cb->compressed_len, cb->nr_pages); } bytes_left -= PAGE_CACHE_SIZE; first_byte += PAGE_CACHE_SIZE; cond_resched(); } bio_get(bio); ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); BUG_ON(ret); ret = btrfs_csum_one_bio(root, inode, bio, start, 1); BUG_ON(ret); ret = btrfs_map_bio(root, WRITE, bio, 0, 1); BUG_ON(ret); bio_put(bio); return 0; } static noinline int add_ra_bio_pages(struct inode *inode, u64 compressed_end, struct compressed_bio *cb) { unsigned long end_index; unsigned long page_index; u64 last_offset; u64 isize = i_size_read(inode); int ret; struct page *page; unsigned long nr_pages = 0; struct extent_map *em; struct address_space *mapping = inode->i_mapping; struct pagevec pvec; struct extent_map_tree *em_tree; struct extent_io_tree *tree; u64 end; int misses = 0; page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; last_offset = (page_offset(page) + PAGE_CACHE_SIZE); em_tree = &BTRFS_I(inode)->extent_tree; tree = &BTRFS_I(inode)->io_tree; if (isize == 0) return 0; end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; pagevec_init(&pvec, 0); while (last_offset < compressed_end) { page_index = last_offset >> PAGE_CACHE_SHIFT; if (page_index > end_index) break; rcu_read_lock(); page = radix_tree_lookup(&mapping->page_tree, page_index); rcu_read_unlock(); if (page) { misses++; if (misses > 4) break; goto next; } page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS); if (!page) break; page->index = page_index; /* * what we want to do here is call add_to_page_cache_lru, * but that isn't exported, so we reproduce it here */ if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) { page_cache_release(page); goto next; } /* open coding of lru_cache_add, also not exported */ page_cache_get(page); if (!pagevec_add(&pvec, page)) __pagevec_lru_add_file(&pvec); end = last_offset + PAGE_CACHE_SIZE - 1; /* * at this point, we have a locked page in the page cache * for these bytes in the file. But, we have to make * sure they map to this compressed extent on disk. */ set_page_extent_mapped(page); lock_extent(tree, last_offset, end, GFP_NOFS); read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, last_offset, PAGE_CACHE_SIZE); read_unlock(&em_tree->lock); if (!em || last_offset < em->start || (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || (em->block_start >> 9) != cb->orig_bio->bi_sector) { free_extent_map(em); unlock_extent(tree, last_offset, end, GFP_NOFS); unlock_page(page); page_cache_release(page); break; } free_extent_map(em); if (page->index == end_index) { char *userpage; size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); if (zero_offset) { int zeros; zeros = PAGE_CACHE_SIZE - zero_offset; userpage = kmap_atomic(page, KM_USER0); memset(userpage + zero_offset, 0, zeros); flush_dcache_page(page); kunmap_atomic(userpage, KM_USER0); } } ret = bio_add_page(cb->orig_bio, page, PAGE_CACHE_SIZE, 0); if (ret == PAGE_CACHE_SIZE) { nr_pages++; page_cache_release(page); } else { unlock_extent(tree, last_offset, end, GFP_NOFS); unlock_page(page); page_cache_release(page); break; } next: last_offset += PAGE_CACHE_SIZE; } if (pagevec_count(&pvec)) __pagevec_lru_add_file(&pvec); return 0; } /* * for a compressed read, the bio we get passed has all the inode pages * in it. We don't actually do IO on those pages but allocate new ones * to hold the compressed pages on disk. * * bio->bi_sector points to the compressed extent on disk * bio->bi_io_vec points to all of the inode pages * bio->bi_vcnt is a count of pages * * After the compressed pages are read, we copy the bytes into the * bio we were passed and then call the bio end_io calls */ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, int mirror_num, unsigned long bio_flags) { struct extent_io_tree *tree; struct extent_map_tree *em_tree; struct compressed_bio *cb; struct btrfs_root *root = BTRFS_I(inode)->root; unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; unsigned long compressed_len; unsigned long nr_pages; unsigned long page_index; struct page *page; struct block_device *bdev; struct bio *comp_bio; u64 cur_disk_byte = (u64)bio->bi_sector << 9; u64 em_len; u64 em_start; struct extent_map *em; int ret; u32 *sums; tree = &BTRFS_I(inode)->io_tree; em_tree = &BTRFS_I(inode)->extent_tree; /* we need the actual starting offset of this extent in the file */ read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, page_offset(bio->bi_io_vec->bv_page), PAGE_CACHE_SIZE); read_unlock(&em_tree->lock); compressed_len = em->block_len; cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); atomic_set(&cb->pending_bios, 0); cb->errors = 0; cb->inode = inode; cb->mirror_num = mirror_num; sums = &cb->sums; cb->start = em->orig_start; em_len = em->len; em_start = em->start; free_extent_map(em); em = NULL; cb->len = uncompressed_len; cb->compressed_len = compressed_len; cb->orig_bio = bio; nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE; cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages, GFP_NOFS); bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; for (page_index = 0; page_index < nr_pages; page_index++) { cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | __GFP_HIGHMEM); } cb->nr_pages = nr_pages; add_ra_bio_pages(inode, em_start + em_len, cb); /* include any pages we added in add_ra-bio_pages */ uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; cb->len = uncompressed_len; comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); comp_bio->bi_private = cb; comp_bio->bi_end_io = end_compressed_bio_read; atomic_inc(&cb->pending_bios); for (page_index = 0; page_index < nr_pages; page_index++) { page = cb->compressed_pages[page_index]; page->mapping = inode->i_mapping; page->index = em_start >> PAGE_CACHE_SHIFT; if (comp_bio->bi_size) ret = tree->ops->merge_bio_hook(page, 0, PAGE_CACHE_SIZE, comp_bio, 0); else ret = 0; page->mapping = NULL; if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) { bio_get(comp_bio); ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); BUG_ON(ret); /* * inc the count before we submit the bio so * we know the end IO handler won't happen before * we inc the count. Otherwise, the cb might get * freed before we're done setting it up */ atomic_inc(&cb->pending_bios); if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { btrfs_lookup_bio_sums(root, inode, comp_bio, sums); } sums += (comp_bio->bi_size + root->sectorsize - 1) / root->sectorsize; ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); BUG_ON(ret); bio_put(comp_bio); comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); comp_bio->bi_private = cb; comp_bio->bi_end_io = end_compressed_bio_read; bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); } cur_disk_byte += PAGE_CACHE_SIZE; } bio_get(comp_bio); ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); BUG_ON(ret); if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) btrfs_lookup_bio_sums(root, inode, comp_bio, sums); ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); BUG_ON(ret); bio_put(comp_bio); return 0; }